A new class of semiconductors that can store information in electric fields could enable computers that run on less power, sensors with quantum precision, and the conversion of signals between electrical, optical and acoustic forms—but how they maintained two opposite electric polarizations in the same material was a mystery.
Opaque materials can transmit light when excited by a high-intensity laser beam. This process, known as optical bleaching, induces a nonlinear effect that temporarily alters the properties of a material. Remarkably, when the laser is switched on and off at ultrahigh speeds, the effect can be dynamically controlled, opening new possibilities for advanced optical technologies.
Multicolored optical switching is an important phenomenon with potential applications in fields such as telecommunications and optical computing. However, most materials typically exhibit single-color optical nonlinearity under intense laser illumination, limiting their use in systems requiring multicolor or multiband switching capabilities. Currently, most optical switches are based on microelectromechanical systems, which require an electric voltage or current to operate, resulting in slow response times.
To address this gap, a group of researchers, led by Professor Junjun Jia from the Faculty of Science and Engineering at Waseda University, Japan, in collaboration with Professor Hui Ye and Dr. Hossam A. Almossalami from the College of Optical Science and Engineering at Zhejiang University, China, Professor Naoomi Yamada from the Department of Applied Chemistry at Chubu University, Japan, and Dr. Takashi Yagi from the National Institute of Advanced Industrial Science and Technology, Japan, investigated the multivalley optical switching phenomenon in germanium (Ge) films.
Physicists at Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have created a compact laser that emits extremely bright, short pulses of light in a useful but difficult-to-achieve wavelength range, packing the performance of larger photonic devices onto a single chip.
Published in Nature, the research is the first demonstration of an on-chip, picosecond, mid-infrared laser pulse generator that requires no external components to operate.
The device can make what’s called an optical frequency comb, a spectrum of light consisting of equally spaced frequency lines (like a comb), used today in precision measurements. The new laser chip could one day speed the creation of highly sensitive, broad-spectrum gas sensors for environmental monitoring, or new types of spectroscopy tools for medical imaging.
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Communication between brain activity and computers, known as brain-computer interface or BCI, has been used in clinical trials to monitor epilepsy and other brain disorders. BCI has also shown promise as a technology to enable a user to move a prosthesis simply by neural commands. Tapping into the basic BCI concept would make smart phones smarter than ever.
Research has zeroed in on retrofitting wireless earbuds to detect neural signals. The data would then be transmitted to a smartphone via Bluetooth. Software at the smartphone end would translate different brain wave patterns into commands. The emerging technology is called Ear EEG.
Rikky Muller, Assistant Professor of Electrical Engineering and Computer Science, has refined the physical comfort of EEG earbuds and has demonstrated their ability to detect and record brain activity. With support from the Bakar Fellowship Program, she is building out several applications to establish Ear EEG as a new platform technology to support consumer and health monitoring apps.
The study notes, “These findings underscore the complexity of Europa’s plume activity. Our results provide a framework to explore various plume characteristics, including gas drag, particle size, initial ejection velocities, and gas production rates, and the resulting plume morphologies and deposition outcomes.”
How do the water vapor plumes on Jupiter’s icy moon, Europa, contribute to the interaction between the moon’s surface and subsurface environments? This is what a recent study published in The Planetary Science Journal hopes to address as a team of researchers investigated how gas drag could influence the direction of particles being emitted by Europa’s water vapor plumes, specifically regarding where they land on the surface, either near the plumes or farther out. This study has the potential to help scientists better understand the surface-subsurface interactions on Europa and what this could mean for finding life as we know it.
Artist’s illustration of Europa’s water vapor plumes. (Credit: NASA/ESA/K. Retherford/SWRI)
For the study, the researchers used a series of computer models to simulate how the speed and direction of dust particles emitted from the plumes could be influenced by a process called gas drag, which could decrease the speed and direction of dust particles exiting the plumes. In the end, the researchers found that gas drag greatly influences dust behavior, with smaller dust particles ranging in size from 0.001 to 0.1 micrometers becoming more spread out after eruption and larger dust particles ranging in size from 0.1 to 10 micrometers landing near the plume sites.
Supported by the U.S. National Science Foundation, physicists have revealed the presence of a previously unobserved type of subatomic phenomenon called a fractional exciton. Their findings confirm theoretical predictions of a quasiparticle with unique quantum properties that behaves as though it is made of equal fractions of opposite electric charges bound together by mutual attraction.
The discovery was supported by NSF through multiple grants and laboratory work performed at the NSF National High Magnetic Field Laboratory in Tallahassee, Florida. The results are published in Nature and show potential for developing new ways to improve how information is stored and manipulated at the quantum level, which could lead to faster and more reliable quantum computers.
“Our findings point toward an entirely new class of quantum particles that carry no overall charge but follow unique quantum statistics,” says Jia Li, leader of the research team and associate professor of physics at Brown University. “The most exciting part is that this discovery unlocks a range of novel quantum phases of matter, presenting a new frontier for future research, deepening our understanding of fundamental physics and even opening up new possibilities in quantum computation.”
Physicists at Harvard have developed a powerful new laser-on-a-chip that emits bright pulses in the mid-infrared spectrum – an elusive and highly useful light range for detecting gases and enabling new spectroscopic tools.
The device, which packs capabilities of much larger systems into a tiny chip, doesn’t need any external components. It merges breakthrough photonic design with quantum cascade laser tech and could soon revolutionize environmental monitoring and medical diagnostics by detecting thousands of light frequencies in one go.
Breakthrough in compact mid-infrared laser technology.
Modern brain–computer interfaces (BCI), utilizing electroencephalograms for bidirectional human–machine communication, face significant limitations from movement-vulnerable rigid sensors, inconsistent skin–electrode impedance, and bulky electronics, diminishing the system’s continuous use and portability. Here, we introduce motion artifact–controlled micro–brain sensors between hair strands, enabling ultralow impedance density on skin contact for long-term usable, persistent BCI with augmented reality (AR). An array of low-profile microstructured electrodes with a highly conductive polymer is seamlessly inserted into the space between hair follicles, offering high-fidelity neural signal capture for up to 12 h while maintaining the lowest contact impedance density (0.03 kΩ·cm−2) among reported articles. Implemented wireless BCI, detecting steady-state visually evoked potentials, offers 96.4% accuracy in signal classification with a train-free algorithm even during the subject’s excessive motions, including standing, walking, and running. A demonstration captures this system’s capability, showing AR-based video calling with hands-free controls using brain signals, transforming digital communication. Collectively, this research highlights the pivotal role of integrated sensors and flexible electronics technology in advancing BCI’s applications for interactive digital environments.